Sandbox construction for shell molding machines



I July 29, 1958 P. KLAMP 2,844,854 SANDBOX CONSTRUCTION FORSHELL MOLDING MACHINES Filed July 1. 1954 2 Sheets$heet 1 IN V EN TOR.

P. KLAMP July 29, 1958 SANDBOX CONSTRUCTION FOR SHELL MOLDING MACHINES Filed July 1, 1954 2 Sheets-Sheet 2 IN V EN TOR. 904 A2 4MP 2,844,854 7 SANDBOX CONSTRUCTION FOR SHELL MULDING MACHINES Paul Klamp', Detroit, Mich., assignor to Mechanical Handling Systems, Inc., Detroit, Micln, a corporation of Michigan Application July 1, 1954, Serial No. 440,604

11 Claims. (Cl. 22-35 This invention relates to improvements in the construction of a container for holding the mold forming composition employed for making shell molds. Such a container is commonly called a sandbox.

The invention is directed to a construction which eliminates dead space or pockets in the container so that all sand or mold forming composition held therein will be employed for making molds; to a construction where means are included for positively controlling the distribution of mold forming material over the pattern surface; and to a construction which can be readily changed or adjusted to provide proper distribution of mold forming material to patterns of different sizes and shapes.

In the usual shell mold forming operation the container or sandbox is inverted over the surface of the pattern to deposit mold forming composition thereon. In the copending application of Paul Klamp and Leonard J. Bishop, now Patent No. 2,762,092, granted September 11, 1956, there is disclosed a shell mold forming machine having a sandbox constructed and operated in such a way that the mold forming composition is deposited upon the pattern surface largely through a lateral shifting movement of the mold forming composition under the influence of gravity. This type of construction has the advantage of reducing the amount of movement that must be imparted to the components of the mold forming machine during the mold forming operation. In other types of shell molding machines with which I am familiar a complete inversion of the sandbox position takes place during the mold forming operation, and no distinguishable.

lateral shifting movement of its contents occurs.

According to the present invention there is provided a container having a storage section for mold forming composition and a dispensing section therefor. The dispensing section includes and practically is defined by the borders of an opening formed in the top of the container and which is adapted to be covered by a pattern plate. The storage section is spaced laterally with respect to the dispensing section and the opening thereof, the mouth of the storage section lying along one wall of the dispensing section. During movement of the container from nor-, mal to depositing position (a movement of less than 180 about a pivotal axis), mold forming composition moves laterally from the storage section of the container into the dispensing section and downwardly onto the surface of the pattern.

Means are included in the container for distributing the mold forming material over the pattern during this lateral movement, in order to prevent the material from piling up on one side of the pattern and leaving voids or thin spots on the other side of the pattern farthest from the. storage section of the container. The distributing means essentially comprises a bathe disposed internallyof the container and providing an extended path for lateral motion of at least a portion of the mold forming composition into the dispensing section of the container, so

that material will fall downwardly over the entire surface of the pattern.

ates Patent In thepreferred form of the invention to be described herein, the baflie means is arranged to act in conjunction with members defining adjacent walls of the storage and dispensing sections of the container, and adjustable with respect thereto to provide a passage for a certain amount of mold forming composition to one side of the pattern and an alternate passage to the other sidethereof. This bathe member can also be provided with slots or apertures to produce a cascading distribution of mold forming composition over, the pattern surface.

A constructional example of the invention is disclosed in the accompanying drawings which comprise the following views:

Fig. 1, a side elevation of a sandbox pivotally supported on the structure of a mold forming machine (not shown). This view depicts the sandbox in a normal position and includes a phantom showing of a pattern carrier and pattern plate;

Fig. 2, a sectional side elevation, showing the sandbox of Fig. l in the depositing or mold forming position thereof--a position where the box has been rotated counterclockwise from the position shown in Fig. 1 through approximately 150;

Fig. 3, a sectional plan view taken along the lines 3-3 of Fig. 2 showing the internal construction of the sandbox and the bafile member thereof; and

Fig.4, a transverse section taken along the lines 4-4 of Fig. 2.

Referring to Fig. 1, the container, generally indicated by the reference 10, is connected by a pair of brackets 11 to a pivot shaft 12, which, in turn, is carried by suitable supporting structure 13 forming part of a molding machine. The -brackets 11 form part of the container structure .so; thatthe container as. a whole is rotatable about the axis of the shaft 12 from the position of Fig. 1 to the. position ofFig; .2 by mechanism (not shown) incorporated in the mold forming machine construction.

Also rotatable about the axis defined by the pivot shaft 12, but formingno part of the present invention, is a able for supporting a pattern such as indicated at 16.

' Fig. 1 gives a representative normal or'upright position a material'storage section 37 .which are of the container 10. Fig. 2 depicts the container in a position where mold forming'composition held therein is deposited over the surface of the pattern 16.

The particular container shown is an irregular-sided box constructed of interconnected sheet metal panels. The side panels 18 (Figs. 3 and .4) are five-sided, as shown in Figs. 1 and 2.; The top of thecontainer is formed by a panel 20 (Fig. 2) and is provided with a rectangular opening bordered by a frame 24 of square tubing. The bottom of the box is formed by a panel 26, bent at an anglealong the line 27, and provided with a removable'section 28 ,held in place by suitable means such as the wing nuts 29. End panels 30 and 31 complete the externalsurfaces of the container.

Preferably, the entire volume of the container is not employed for holding mold forming composition. Instead, ;thetrue internal volume of the container is .defined by a panel 32 extending between and connected to the side panels 18, and bent to provide a portion 33 and a portion 34. The panel 32 serves to eliminate the dead space or pocketwhich would occur at the corner of the 7 container lgiaving a, material dispensing section 36 and l laterally sepa-- rated in both verticaliand horizontal directions. L Portion 33 of panel" 32 forms ;a wajll of the dispensing. section. 36 of the" c tainer while portion 3 41 forms a walljof the jhefifl L e a inte se io Y bet-ween theaad 'aceatwalls 33 and 34- of the dispensing and storage sections is generally parallel to the axis defined by the pivot shaft 12.

The angular relationship between certain of the wall panels of the container is generally related to the fiow characteristics and angle of repose of the material .being handled; By angle of repose is meant an angle, .measured from a horizontal line, to which a mass of material having an approximately level surface can be movedor tilted without appreciable flow or shifting thereof. For example, consider a drum or cylinder partially filled with a granular material and rotatably mounted on an axis coinciding with the axis of the cylinder. If the drum is placed in a position where the surface of the material therein is approximately horizontal, the drum can be rotated in either direction through a certain number of degrees and the surface of the material will define an increasing angle to the horizontal. Up to a certain angle, the surface is stable. Beyond that angle, which is called herein the angle of repose, the material begins to shift position. If rotary motion of the drum is continued through a given number of degrees, it will be found that when motion of the drum is stopped, the angle between the surface of the material and the horizontal will still be approximately equal to the angle of repose. For a fine granular material, such as shell molding composition, the angle of repose is slightly less than 30.

It can thus be seen why more than merely 90 of movement is employed for the sandbox construction shown. When the sandbox is turned to mold forming or depositing position, as shown in Fig. 2, movement iscontinued to a position approximately 30 beyond the horizontal to bring the level of mold forming composition over the pattern approximately to the horizontal and thus insure that all portions of the pattern are covered by the composition. Likewise, when the sandbox is returned to normal position, its. movement is continued to approximately 45 past a vertical position to compensate for the angle ofrepose of the mold forming material and insure that all excess material will fall away from the pat tern surface and back into the storage section of the container. a r

The contour of the internal panel 32 is related to some extent to the extreme limits of movement-normal and depositing positions-43f the container; Thusin the normal position of Fig. l the section 33 of the'panel 32 lies at an angle greater than the angle of repose of the material. Likewise, in the depositing position of Fig. 2, the section 34 of the panel 32 lies at an-angle greater than the angle of repose of the material.

With this description of the sandbox construction in mind, it can beseen from a comparison of the sandbox position in Figs. land 2 that the movement of material in the container is lateral and downward as the container is rotated from one position to another.

In order to provide for such lateral movement of the material to all sides of the pattern surface to be covered, means are included for controlling the distribution of material during its lateral and downward movement as the container is rotated to mold forming position (Fig. 2'). Such means may comprise the transversebaflie plate 40 illustrated, mounted in the container at an angle at least greater than the angle of repose of the material with respect to the depositing or mold forming position of the container. This plate 40 in the specific construction illustrated is provided with downturned stifiening ribs 41 and extends from the mouth of the storage section 37 across the dispensing section 36 to a locationintermediate the sides of pattern opening of the container.

In the preferred construction shown, the plate 40 is adjustably mounted. This mounting comprises an at-v tachment of, the plate to a pivot shaft 42, carried between the sides 18 of the container. A latch bar 44, supported by a bracket 45, attached to the container wall.

26 extends through a slot 46 in the panel-40, and the agesection is provided with a surface across whichthe;

latch bar is provided with a series of notches 48 dimensioned for frictional engagement with the panel. This permits the position of the free end 50 of the panel 40 to be adjusted with relation to the surface 34, providing an opening between the panel and surface 34 of variable width through which mold forming material passes to one side of the pattern area. Other material will pass over the top surface of the panel 40 and be delivered to the other side of the pattern area. If desired, portions 'f the material being delivered across the top of the panel to the pattern area can bediverted by providing transverse slots 46 in the surface thereof. It the panel 40 is employed in the position indicated in dotted line in Fig. 2, all material coming from the storage section of the container to the dispensing section thereof will pass across the surface of the panel, and in such case slots will usually be found desirable to provide a cascading action of material falling onto the pattern surface. A limited pivotal movement of the panel can be employed to assist the return of excess mold forming material from the pattern area to the storage section of the container when the latter is returned to its-normal position as shown in Fig. 1. In such case the panel 40 would act somewhat in the manner of a flap valve.

To a large extent, the problem of obtaining proper distribution of mold forming material over the pattern area will bea function of the pattern shape. If improperdistribution is being obtained to any portion of the pattern surface, additional mold forming material can readily be supplied to the necessary portion of the pattern area by either adjusting the position of the baffle plate 40 or by providing suitable apertures therein, or by a combination of both. The plate 40 is simple in-construction and quite inexpensive, so that no problem is presented by the necessity of having to make any particular modifications in the plate to overcome a distribution problem on a particular pattern.

In many cases where the shell molding process is employed, the articles'being manufactured will be a longproduction, high-volume run, and in such case the baffle plate 40 will frequently be fixed in one position in the container, such as by Welding, and the pivotal attachment and adjustable features eliminated. As a matter of fact, a fixed position of the baffie plate in the approximate position illustrated, will be found adequate for practically all mold forming operations. .It is only the exceptional pattern that will present an additional distribution problem.

The specific constructional features illustratedand described herein will naturally have to be modified to adapt. the invention to use with specific designs of mold forming machines. Such modifications are to be considered as part of the scope of the present invention included within the definition thereof contained in the following claims.

I claim:

1. A mold forming composition container for a shell molding machine adapted to be rotated about a substantially horizontal axis between a normal position and a depositingposition and provided with a top having an opening adapted to be registered with a pattern, side and end panels bordering said opening and forming walls of a dispensing section of said container surrounding the area of said opening, said side panels being disposed perpendicular to said pivotal axis, and to the plane of said opening, at least one of said end panels being disposed at an oblique. angle to the plane of said opening, and a storage section disposed in lateral relation to said opening and communicating with one end of said dispensing section at a mouth portion, one edge of which is definedby saidobliquely disposed end panel.

2. A container according to claim 1 wherein the stormold forming composition moves in shiftingto the dispensing section, said surface intersecting said obliquely disposed end panel at the said edge of the storage section and being disposed at an angle to the horizontal greater than the angle of repose of the composition when the container is in the depositing position.

3. A container according to claim 1 wherein said obliquely disposed end panel forms a surface across which the mold forming composition moves in shifting from the dispensing to the storage section, said surface being disposed at an angle to the vertical greater than the angle of repose of the composition when the container is in normal position.

4. A container according to claim 1 further characterized by a material distributing plate located in said dispensing section and extending toward the mouth portion of said storage section whereby at least a portion of the material moving to said dispensing section from said storage section on pivotal motion of said container travels across said distributing plate.

5. A container according to claim 4 further characterized by said material distributing plate being provided with a plurality of openings successively arranged in the path of movement of mold forming composition shifting from said storage section to said dispensing section.

6. A container as set forth in claim 1, wherein said container is further characterized by a baffle plate mounted between the said side members of said depositing section and having one edge thereof adjacent the said one edge of the mouth of said storage section.

7. A container as set forth in claim 6 wherein said baffle plate is mounted on a pivotal axis perpendicular to the sides of said container whereby the distance between the said edge of said baflie member and the said edge of said storage section mouth can be varied by movement of said bafile member about said pivotal axis, and means for retaining said bafile member in a selected position.

8. A container for a shell molding machine of the type having a substantially horizontal pivotal axis upon which the container is mounted for movement between a normal position and a depositing position, said container being provided with a top having an opening adapted to be registered with a pattern, the entire area of said opening being spaced laterally from said pivotal axis, side and end panels bordering siad opening and forming walls of a dispensing section of said container surrounding the area of said opening, said side panels being disposed perpendicular to said pivotal axis, one of molding machine of the type having a pivotal axis upon which the container is mounted for movement between a normal position and a depositing position, said container having a top provided with an opening adapted to be registered with a pattern, said opening being spaced laterally from said pivotal axis, the internal volume of said container being composed of two sections, one a storage section and the other a dispensing section, said dispensing section being adjacent said opening and said storage section projecting laterally from said dispensing section, said storage section and said dispensing section each including a wall panel forming a surface across which the mold forming composition moves in shifting from one section to the other upon movement of said container from normal position to depositing position and return, said wall panels intersecting on a line parallel to said pivotal axis.

10. A mold forming composition container for a shell moldit. g machine of the type having a pivotal axis upon which the container is mounted for movement between a normal position and a depositing position, said con- .tainer having a top provided with an opening adapted to be registered with a pattern, said opening being spaced laterally from said pivotal axis, the internal volume of said container being composed of two sections, one a storage section and the other a dispensing section, said dispensing section being adjacent said opening and said storage section projecting laterally from said dispensing section, said storage section and said dispensing section each including a wall panel forming a surface across which the mold forming composition moves in shifting from one section to the other upon movement of said container from normal position to depositing position and return, said wall panels intersecting on a line substantially parallel to said pivotal axis with the included angle between said wall panels being greater than 11. A container as set forth in claim 10 further pro vided with a baffle member extending from a location adjacent the said line of intersection of said wall panels and extending over the area of said opening, said bafile member having a plurality of openings successively arranged in the path of movement of mold forming composition shifting from said storage section to said dispensing section.

References Cited in the file of this patent UNITED STATES PATENTS OTHER REFERENCES Foundry, November 1952, page 265. Copy in Sci. Libr. 

